Cable Section Fault Detection for HVDC Line Protection

For DC line protection of the Hokkaido-Honshu HVDC Link, a submarine cable fault detection system was developed. In this system, a DC line fault is declared when DC currents at both cable heads change mutually in the reverse direction. Combining this detection system with a current difference detection system which operates for any fault occurring on the high voltage DC transmission line, the high voltage DC line protection system is composed. Through the simulator tests and five-year field experience, the detection system has been verified to be satisfactory.